Britain had a functioning consular service in Japan from 1859 after the signing of the 1858 Anglo-Japanese Treaty of Amity and Commerce between James Bruce, 8th Earl of Elgin and the Tokugawa Shogunate until 1941 when Japan invaded British colonial empire and declared war on the United Kingdom.
The Consular Service was established with officials who were expected to serve their entire careers in Japan. The entry-level position was as student interpreter who were expected to learn Japanese. In the early years almost all dealings with Japanese officials were in Japanese and British consular officials had a high standard in the spoken and written language. This declined over time as more Japanese officials learnt English.
Until 1899, British Consular Officials exercised extraterritorial jurisdiction over British subjects in Japan. Consular officials sat as judges in consular courts in all treaty ports. Until 1865 appeals from decisions of consular officials were made to the Supreme Court of Hong Kong. From 1865 appeals from decisions could be made to the British Supreme Court for China and Japan in Shanghai. From 1871 to 1878 a judge from Shanghai was based in Yokohama sitting first as a branch of the British Supreme Court for China and Japan. Later they were treated as a judge of the Kanagawa Consular Court. In 1879 a British Court for Japan was created in Yokohama which had first instance jurisdiction in Kanagawa and appellate jurisdiction from other consular courts in Japan. Appeals from the Court for Japan lay to Supreme Court in Shanghai.